IPHAS Sample SQL Queries

This page provides examples of queries against the IPHAS catalogue using AstroGrid. You can type (or copy'n'paste) the query in the Query Builder window as shown in the image below.

Example queries

Search for objects around a position

This is the most basic query returning all objects in a specific box:

SELECT * FROM
  PhotoObjBest as P
WHERE
  P.ra > 15.4 AND P.ra < 15.6
  AND
  P.dec > 59.0 AND P.dec < 60.1

Cone search

Return coordinates and magnitudes of objects in a cone defined by its center at RA=300.0 and Dec=30.0 and radius r=10 arcmin. In this case instead of coding the whole trigonometry in the query we use the auxiliary table tGetNearbyObj which returns the object IDs which satisfy a cone search specified by the center coordinates (ra, dec) and radius (r) in minutes of arc:

SELECT 
  P.ra, P.dec, P.coremag_r, P.coremag_i, P.coremag_ha, 
  P.coremagerr_r, P.coremagerr_i, P.coremagerr_ha 
FROM 
  PhotoObjBest as P, tGetNearbyObj as G 
WHERE 
  G.ra=300.0 AND G.dec=30.0 AND G.r=10.0 AND P.objID = G.objID 

Object classification and additional constraints

As previous example but only return objects classified as point-like in r and observed in conditions of seeing better than 1.5 arcsec as measured in the r band.

In this query we are asking for information about the quality of observations and this is stored in the ChipsAll table. We need therefore to join the results with this table in order to select only observation with good seeing conditions.

SELECT 
   P.ra, P.dec, P.coremag_r, P.coremag_i, P.coremag_ha, 
   P.coremagerr_r, P.coremagerr_i, P.coremagerr_ha 
FROM 
   PhotoObjBest as P, tGetNearbyObj as G, ChipsAll as CR 
WHERE 
   G.ra=300.0 AND G.dec=30.0 AND G.r=10.0
   AND CR.seeing<1.5 AND (P.class_r=-1 OR P.class_r=-2)
   AND P.objID = G.objID AND P.chipsall_r=CR.chipID

Adding additional constraints on e.g. object colours, magnitude limits, observation dates are trivially implemented in the same way, e.g.:

SELECT 
   P.ra, P.dec, P.coremag_r, P.coremag_i, P.coremag_ha, 
   P.coremagerr_r, P.coremagerr_i, P.coremagerr_ha 
FROM 
   PhotoObjBest as P, tGetNearbyObj as G, ChipsAll as CR 
WHERE 
   G.ra=300.0 AND G.dec=30.0 AND G.r=10.0 
   AND P.coremag_r-P.coremag_ha>0.8 
   AND P.coremag_r-P.coremag_i>1.5 
   AND P.coremagerr_r<0.02 

Objects by field

Select all objects observed in a particular field in the off position.

The following example returns all objects detected in a particular observation from the (not cleaned) PhotoObj catalogue.

SELECT * FROM PhotoObj as P  FieldsAll as F
WHERE F.fieldID = P.field_id AND F.fieldno=7012 AND F.onoff=0